ArcGIS Runtime SDK for Java

Identify Layers

Demonstrates how to identify clicked features from multiple layers.

How it works

To identify features from layers in a map:

  1. Get a Point2D with the screen location where the user clicked.
  2. Call mapView.identifyLayersAsync(screenLocation, tolerance, returnPopupsOnly, maximumResults).
  3. Get the list of IdentifyLayerResults from the result. You can get the identified GeoElements in the layer with identifyLayerResult.getElements().
  4. To find identified GeoElements in sublayers, use identifyLayerResult.getSublayerResults() and repeat the last step.

Code

/*
 * Copyright 2018 Esri.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package com.esri.samples.mapview.identify_layers;

import java.util.List;
import java.util.concurrent.ExecutionException;

import javafx.application.Application;
import javafx.geometry.Point2D;
import javafx.scene.Scene;
import javafx.scene.control.Alert;
import javafx.scene.input.MouseButton;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

import com.esri.arcgisruntime.concurrent.ListenableFuture;
import com.esri.arcgisruntime.data.FeatureTable;
import com.esri.arcgisruntime.data.ServiceFeatureTable;
import com.esri.arcgisruntime.geometry.Point;
import com.esri.arcgisruntime.geometry.SpatialReference;
import com.esri.arcgisruntime.layers.ArcGISMapImageLayer;
import com.esri.arcgisruntime.layers.FeatureLayer;
import com.esri.arcgisruntime.loadable.LoadStatus;
import com.esri.arcgisruntime.mapping.ArcGISMap;
import com.esri.arcgisruntime.mapping.Basemap;
import com.esri.arcgisruntime.mapping.Viewpoint;
import com.esri.arcgisruntime.mapping.view.IdentifyLayerResult;
import com.esri.arcgisruntime.mapping.view.MapView;

public class IdentifyLayersSample extends Application {

  private MapView mapView;

  /**
   * Opens and runs application.
   *
   * @param args arguments passed to this application
   */
  public static void main(String[] args) {

    Application.launch(args);
  }

  @Override
  public void start(Stage stage) {

    try {
      // create stack pane and application scene
      StackPane stackPane = new StackPane();
      Scene scene = new Scene(stackPane);

      // set title, size, and add scene to stage
      stage.setTitle("Identify Layers Sample");
      stage.setWidth(800);
      stage.setHeight(700);
      stage.setScene(scene);
      stage.show();

      // create a map with an initial viewpoint
      ArcGISMap map = new ArcGISMap(Basemap.createTopographic());
      map.setInitialViewpoint(new Viewpoint(new Point(-10977012.785807, 4514257.550369, SpatialReference.create(3857)), 68015210));

      // set the map to a map view
      mapView = new MapView();
      mapView.setMap(map);

      // add a map image layer with one sublayer visible
      ArcGISMapImageLayer mapImageLayer = new ArcGISMapImageLayer("https://sampleserver6.arcgisonline.com/arcgis/rest/services/SampleWorldCities/MapServer");
      mapImageLayer.addDoneLoadingListener(() -> {
        if (mapImageLayer.getLoadStatus() == LoadStatus.LOADED) {
          // hide Continent and World layers
          mapImageLayer.getSubLayerContents().get(1).setVisible(false);
          mapImageLayer.getSubLayerContents().get(2).setVisible(false);
        } else {
          new Alert(Alert.AlertType.ERROR, "Failed to load the map image layer").show();
        }
      });
      map.getOperationalLayers().add(mapImageLayer);

      // add a feature layer
      FeatureTable featureTable = new ServiceFeatureTable("https://sampleserver6.arcgisonline.com/arcgis/rest/services/DamageAssessment/FeatureServer/0");
      FeatureLayer featureLayer = new FeatureLayer(featureTable);
      featureLayer.addDoneLoadingListener(() -> {
        if (mapImageLayer.getLoadStatus() != LoadStatus.LOADED) {
          new Alert(Alert.AlertType.ERROR, "Failed to load the feature layer").show();
        }
      });
      map.getOperationalLayers().add(featureLayer);

      // create map view click listener
      mapView.setOnMouseClicked(e -> {
        if (e.isStillSincePress() && e.getButton() == MouseButton.PRIMARY) {

          // identify layers with GeoElements where the user clicked
          Point2D point2D = new Point2D(e.getX(), e.getY());
          ListenableFuture<List<IdentifyLayerResult>> identifyResults = mapView.identifyLayersAsync(point2D, 12, false, 10);
          identifyResults.addDoneListener(() -> {
            try {
              // build a string with the total count of identified GeoElements for each layer
              StringBuilder resultsList = new StringBuilder();
              List<IdentifyLayerResult> results = identifyResults.get();
              // for each result layer, recursively search its sublayers to get the total count of GeoElements
              for (IdentifyLayerResult result : results) {
                int recursiveGeoElementCount = searchGeoElements(result);
                resultsList.append(result.getLayerContent().getName()).append(": ").append(recursiveGeoElementCount).append("\n");
              }
              // show the result counts string in a dialog
              String resultString = resultsList.toString();
              Alert alert = new Alert(Alert.AlertType.INFORMATION, resultString.equals("") ? "No Results" : resultString);
              alert.initOwner(mapView.getScene().getWindow());
              alert.show();
            } catch (InterruptedException | ExecutionException ex) {
              new Alert(Alert.AlertType.ERROR, "Failed to identify layers").show();
            }
          });
        }
      });

      // add the map view to stack pane
      stackPane.getChildren().add(mapView);
    } catch (Exception e) {
      // on any error, display the stack trace.
      e.printStackTrace();
    }
  }

  /**
   * Searches an identify layer result recursively to find the identified GeoElements for all identified sublayers.
   *
   * @param layerResult identify layer result
   * @return recursive identified GeoElements count
   */
  private int searchGeoElements(IdentifyLayerResult layerResult) {
    int identifiedSubLayerGeoElements = 0;
    for (IdentifyLayerResult subLayerResult : layerResult.getSublayerResults()) {
      identifiedSubLayerGeoElements += searchGeoElements(subLayerResult);
    }
    return layerResult.getElements().size() + identifiedSubLayerGeoElements;
  }

  /**
   * Stops and releases all resources used in application.
   */
  @Override
  public void stop() {

    if (mapView != null) {
      mapView.dispose();
    }
  }

}


In this topic
  1. How it works
  2. Code